In the field of network connectivity, market interest in smaller diameter network cabling has been increasing. Smaller diameter cabling reduces manufacture cost and the amount of resources used for the cabling. In some markets, 28 and 30 AWG conductor network cable is being used. Consequently, interest in communication jacks which are compatible with four twisted pair (CAT5E, CAT6, CAT6A, for examples) network cabling using 28 and 30 AWG wire has been increasing as such jacks can provide an end user with a complete channel solution using the 28 or 30 AWG conductor cable.
For some applications, a 100 meter channel is not needed and consequently the insertion loss budget available for a 100 meter channel can be used for a shorter channel length with a cable having smaller conductors (and therefore higher insertion loss). One of the challenges of providing a jack compatible with 28 and 30 AWG conductor cable is that, although the smaller cable conductors provide the advantages of having smaller diameter and being more flexible, there can be difficultly in obtaining appropriate strain relief between the jack and cable.
During the installation of a structured cabling system, strain may be applied to horizontal cable runs that are terminated to mounted modular jacks. One cause of strain on a horizontal cable run may be a technician pulling new horizontal cable runs in close proximity to the existing horizontal cable runs. Another cause of strain on a horizontal cable run may be a technician placing existing horizontal cable runs routed in similar locations into cable bundles. These cable bundles may increase the strain applied to each individual horizontal cable run. Yet another cause of strain on a horizontal cable run may be a technician installing a horizontal cable run with insufficient slack. The horizontal cable run may then need to be pulled taut to reach the mounting location of the modular jacks and this may introduce a constant strain onto the horizontal cable run.
Strain may also be applied to horizontal cable runs that are terminated to mounted modular jacks after the structured cabling system has been installed. A major cause of this strain on a horizontal cable run may be a network administrator rearranging the location of particular modular jacks or cables in the structured cabling system. After removing a modular jack from its mounted position, the network administrator may apply strain on the horizontal cable run by pulling the modular jack and the terminated horizontal cable run to its new location. The network administrator may also place the modular jack in a new mounting location where the terminated horizontal cable run does not have sufficient slack, which may introduce a constant strain onto the horizontal cable run.
Applying strain to a terminated horizontal cable run may introduce problems in the termination area of a modular jack. One problem with applying strain to a horizontal cable run is that the wire pairs of the cable may be partially or fully pulled out of the insulation displacement contact (“IDC”) terminals of the modular jack, which may result in wire containment cap failures or variability in modular jack performance. Another problem with applying strain to a horizontal cable run is that the strain may damage the IDC terminals of the modular jack. Yet another problem with applying strain to a horizontal cable run, and particularly constant strain, is that over time the strain may cause the horizontal cable insulation near the termination area of the modular jack to pull back, rip or tear apart and expose live wire pairs. Any exposure of live wire pairs may present a safety hazard, result in a short circuit, or change the electrical performance of the modular jack.
U.S. Pat. No. 7,452,245 (Doory et al.) and U.S. Pat. No. 7,476,120 (Patel et al.), which are herein incorporated by reference in their entirety, disclose communication jacks having wire containment caps with strain relief clips which can prevent the wire pairs of the cable from pulling out of the jack terminals due to horizontal strain by providing pressure on the cable to hold the cable in place relative to the jack housing. These designs are versatile and can easily accommodate network cabling with stranded or solid conductors in the range of 22-26 AWG (corresponding to a 0.0253-0.0159 inch conductor diameter range, respectively) which is typical of ANSI/TIA 568 standard compliant cable. Although the '245 and '120 inventions can be used with network cable using 28 and 30 AWG conductors (corresponding to 0.0126 and 0.0100 inch conductor diameters, respectively), special considerations need to be taken into account when applying strain relief to the smaller conductor cable.
Generally, network cable using 22-26 AWG conductors are: 1) relatively easy to terminate to jack IDCs with good conductor/IDC retention; 2) relatively stiff; 3) relatively large; and 4) and due in part to the aforementioned 2) and 3) characteristics, have a relatively small deformation for a given compression (gripping) to provide strain relief with adequate retention. Relatively small cable deformation can be advantageous because the twisted pair conductors can maintain their relative positioning. Deformation of the twisted pairs can result in degradation of electrical performance of the channel, particularly return loss, and also possibly NEXT degradation. Network cabling using 28 and 30 AWG conductors which has the advantages of small cable size, improved cable flexibility, lower cost, and relatively small conductor diameters, is generally more challenging to terminate to jack IDCs with good conductor/IDC retention and has a relatively large deformation for a given compression (gripping) to provide strain relief with adequate retention.